This application relates to electrical panelboards, also known as powerpanels, and switchboards. More specifically, this application relates to trim plates for use with electrical panelboards and switchboards.
Panelboards and switchboards are enclosures used in electrical distribution systems for the mounting of various electrical distribution components. Such components may include switches, protective devices (e.g., circuit breakers), and instruments. These components are mounted to a plurality of mounting rails within the panelboard or switchboard and receive electrical power via buses that extend within the panelboard or switchboard.
A panelboard (powerpanel) includes a single faze panel or group of panel units designed for assembly in the form of a single face panel. The face panel is mounted to a cabinet or box assembly, which is placed against a wall or partition. Panelboards are accessible from the front. Panelboards are often fitted with an external door, known as a "door-in-door" or "single door" enclosure, to prevent unauthorized access to the electrical distribution components. A "power panelboard" is a panelboard having less than a certain percentage of its over-current devices protecting lighting and appliance branch circuits.
A switchboard includes a large single panel, frame, or assembly of panels having the electrical components mounted on the face panel or back panel or both. Switchboards may be accessible from the rear, the front, or the sides.
The face panel of a panelboard or switchboard can include a four-piece front, a single piece front or a door. A four-piece front is typically constructed from four substantially flat panels configured in a single plane to form a perimeter around a central opening. The central opening in the face panel allows access to the electrically active (live) portions of the electrical distribution components mounted in the panelboard or switchboard. A single piece front is similar to a four-piece front, but is formed from a single, substantially flat panel having an opening formed in a central portion. In a door-in-door enclosure, an electrical safety panel, called a "dead front", is mounted behind a door. The dead front is typically formed from four-pieces, with flanges extending from the panels to form a perimeter around the dead front. Like the single piece front and the four-piece front, the dead front has a central opening formed therein to allow access to the electrically active portions of the electrical distribution components.
To prevent personnel from contacting the electrically active parts of the electrical distribution components, a plurality filler plates (cover plates) are positioned across the central opening. The filler plates may have one or more apertures through which the operating handles of the electrical distribution components extend. Alternatively, the filler plates may have no apertures (blank) to cover portions of the central opening where no electrical distribution components are mounted. A typical panelboard or switchboard will have a number of different types of filler plates to accommodate different arrangements of electrical distribution components within the panelboard or switchboard.
In modem power panelboards and switchboards, filler plates are secured to the mounting rails along with the electrical distribution components. Typically, a mounting tab extends from the mounting rails to secure the filler plates above the electrical distribution components. In order to remove the filler plates, a technician must first remove the face panel, which is secured to the cabinet or box assembly by a plurality of screws disposed around the perimeter of the face panel. Next, each filler plate must be removed individually. In sum, removal of one or more of the individual filler plates is a time consuming process that increases the amount of time needed to perform routine maintenance on the electrical distribution components. In addition, if the mounting tab were to break, replacement of the broken tab could require removal of an individual electrical distribution component, which increases maintenance time.